Coregonus lavaretus | |
---|---|
European whitefish (Coregonus lavaretus) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Salmoniformes |
Family: | Salmonidae |
Genus: | Coregonus |
Species: | C. lavaretus |
Binomial name | |
Coregonus lavaretus | |
Synonyms | |
Coregonus oxyrinchus(Linnaeus, 1758) |
Coregonus lavaretus is a species of freshwater whitefish, in the family Salmonidae. It is the type species of its genus Coregonus . [2]
There are widely different concepts about the delimitation of the species Coregonus lavaretus and about the number of species in the genus Coregonus in general.
In a narrow sense, Coregonus lavaretus, or the lavaret, is considered to be endemic to Lake Bourget and Lake d’Aiguebelette in the Rhône river basin in France, whereas it formerly also occurred in Lake Geneva. [1] According to this view there is a great number of distinct whitefish species in lakes, rivers and brackish waters of Central and Northern Europe. [2]
In the broad sense, Coregonus lavaretus, in English referred to as the common whitefish or European whitefish, is widespread from central and northwest Europe to Siberia. [3] Often called the C. lavaretus complex and considered as a superspecies, it encompasses many of the whitefish populations suggested by others to be locally restricted species (such as the British powan and the gwyniad or the Alpine gravenche, as well as distinct intralacustrine morphs and populations characterized by different feeding habits, gill raker numbers, growth patterns and migration behaviour. Genetic studies suggest that the whitefish diversity within this complex is mostly of post-glacial origin. [4] The resource polymorphism represented by the feeding morphs has evolved repeatedly and independently within individual lakes, and similar morphs in different lakes are not closely related to each other. [4]
There is much variation among the European whitefish forms, but in general they have a tapered body, a slightly protruding upper jaw and a fleshy dorsal fin that is typical of the salmon family. The snout is short and tapered, a fact that distinguishes this species from the two other North European Coregonus species, vendace (Coregonus albula) and the introduced peled (Coregonus peled). The former has a protuberant lower jaw while in the latter, the jaws are equal in length. The back is bluish green or brownish, the flanks silvery and the belly white. The fins are dark grey. This fish seldom grows more than 55 cm (22 in) long or exceeds 2 kg (4.4 lb) in weight. [5]
The European whitefish mostly feed on bottom-dwelling invertebrates or zooplankton. Larger fish also take insects off the surface of the water and eat fish fry. Breeding takes place in the autumn between September and November, largely depending on the water temperature. Different populations in the same sections of water may spawn at different times. Many populations in seas and lakes tend to make their way up-river to spawn, but others populations remain in lakes or the sea even when breeding. [5]
The houting (Coregonus oxyrhinchus) is a European species of whitefish in the family Salmonidae that was long thought extinct. It was native to the estuaries and rivers draining to the North Sea. The houting is distinguishable from other Coregonus taxa by having a long, pointed snout, an inferior mouth and a different number of gill rakers. [6] [7] The houting once occurred in Belgium, France, Germany, the Netherlands and England. In 2023, DNA analysis found the houting to be genetically indistinguishable from Coregonus lavaretus, and therefore not extinct. [8] [9]
There is controversy whether whitefish surviving in the southeastern North Sea sector of Denmark (Wadden Sea) and considered there as houting (Danish: snæbel) represent the same species as the houting that was extirpated from the more southwestern parts of the North Sea. [10] [11] Like the more southwestern population, the Danish North Sea population has a long, pointed snout and an inferior mouth, and it is anadromous, spending most of its adult life in coastal waters, but migrating into rivers to breed (some other European Coregonus occur in brackish water, but the ability to live long-term in full salt water is unique to the houting). [10] [12]
The Danish houting is genetically part of the widespread Coregonus lavaretus complex (including Coregonus maraena of the Baltic Sea basin; some prefer to include the Danish houting in this species), while its genetic relationship to the extinct population cannot be confirmed due to a lack of sufficient samples of the latter. [10] [13] Nevertheless, there are some minor differences in the genetics of the Danish houting compared to other living members in the C. lavaretus complex, as well as the differences in morphology and ecology, making it an evolutionarily significant unit. [10] [13] [14] Hybridization and introgression between North Sea houting and its relatives is well-documented, and likely the result of translocations of Coregonus between different regions by humans. [14] Some researchers argue that the morphological differences between different houting populations are not exceptional within the broader variation of the European whitefish, and probably no species-level extinction has taken place. [10] [15] The primary reason for treating the Danish houting and the extinct houting as separate are differences in the number of gill rakers (on average, the Danish has fewer than the extinct), but this number can vary extensively in Coregonus, even within a single population and species, [12] [16] and genetic studies of Coregonus have shown that gill rakers are of limited use in predicting relationship among populations. [17] [18] Some think that the morphological differences in number of gill rakers are sufficient for treating them as separate, and that the last true houting was caught in the lower Rhine in 1940. [6] Studies in the early 2000s (decade) indicated that there was no overlap in the possible number of gill rakers of the two (28–35 in the Danish; 38–46 in the extinct), [6] [7] but later reviews have shown that there is an overlap (up to 41 has been found in the Elbe, a reintroduced population based on Danish houting). [19]
A €13 million restoration project of the Danish houting, partly funded by the European Union's LIFE programme and the Danish Natural Agency, was undertaken in 2005–2013, [20] [21] and there is ongoing monitoring of the species and regulation of the fish-eating great cormorant from important locations. [22] As of 2019, a total of more than €20 million has been used on its conservation, with almost two-thirds funded by Denmark and the remaining by the European Union. [23] However, the only remaining fully natural and significant population of Danish houting is in the Vidå River, estimated in 2014 to consist of about 3,500 adults. Little is known about its exact spawning and juvenile requirements, and despite the earlier project it was still declining, leading to fears that it could become fully extinct unless more is done to preserve it. [22] After years with a downward trend in its numbers, an increase to about 4,000 adult Danish houtings was registered in 2018–19, with most individuals in the Vidå and fewer in Ribe River (both populations increasing). [23]
Individuals from the Danish population have been used as a basis for re-establishing houting in the Eider, Elbe (both indisputably a natural part of the range) and Rhine (arguably non-native, if the extinct is recognized as a separate species). [19] [24] [25] On the 24th of October 2023 researchers of the Research Institute for Nature and Forest in Belgium captured a live specimen in the Scheldt river in Kruibeke, while the species was thought to be extinct in the country for over 100 years. Possibly the specimen migrated there from the Rhine population. [26] In Annex II of the EC Habitats Directive (92/43/EEC), a species listed as Coregonus oxyrhynchus[ sic ] is protected for 'anadromous populations in certain sectors of the North Sea' [27]
In 2023, DNA analysis found the houting to be genetically indistinguishable from Coregonus lavaretus, and therefore not extinct. [28] [9]
Coregonus is a diverse genus of fish in the salmon family (Salmonidae). The Coregonus species are known as whitefishes. The genus contains at least 68 described extant taxa, but the true number of species is a matter of debate. The type species of the genus is Coregonus lavaretus.
The ciscoes are salmonid fish that differ from other members of the genus Coregonus in having upper and lower jaws of approximately equal length and high gill raker counts. These species have been the focus of much study recently, as researchers have sought to determine the relationships among species that appear to have evolved very recently. Cisco is also specifically used for the North American species Coregonus artedi, also known as lake herring.
The gwyniad is a freshwater whitefish native to Bala Lake in northern Wales.
The powan is a kind of freshwater whitefish endemic to two lochs in Scotland, Loch Lomond and Loch Eck. It has been successfully introduced in two other sites, Loch Sloy and the Carron Valley Reservoir.
The pollan or Irish pollan is a freshwater whitefish known only from five Irish lakes, Lough Neagh, Lower Lough Erne, Lough Ree, Lough Derg and Lough Allen. The pollan faces competition from introduced species such as pike, roach and zebra mussel, and the populations rely on restocking for survival.
The blackfin cisco was a North American salmonid fish in the freshwater whitefish sub-family Coregoninae. This silvery, deep-bodied fish with black fins, large eyes, a blunt snout and a terminal mouth, was one of the largest forms of ciscoes. The blackfin cisco used to inhabit the Great Lakes of North America until recently, but has been reported to have gone extinct. The blackfin cisco is a member of the C. artedi complex, whose taxonomy has not yet been resolved, and it may not represent a valid species.
The omul, Coregonus migratorius, also known as Baikal omul, is a whitefish species of the salmon family endemic to Lake Baikal in Siberia, Russia. It is considered a delicacy and is the object of one of the largest commercial fisheries on Lake Baikal. In 2004, it was listed by an unknown group in Russia as an endangered species.
Coregonus albula, known as the vendace or as the European cisco, is a species of freshwater whitefish in the family Salmonidae. It is found in lakes in northern Europe, especially Finland, Latvia, Lithuania, Sweden, Russia and Estonia, and in some lakes of Norway, the United Kingdom, northern Germany, and Poland. It is also found in diluted brackish water in the Gulfs of Finland and Bothnia, both of which are in the Baltic Sea.
The broad whitefish is a freshwater whitefish species. Dark silvery in colour, and like a herring in its shape. Its distinctive features includes: a convex head, short gill rakers, and a mild overbite. It is found in the Arctic-draining streams, lakes, and rivers of far eastern Russia and North America. Its prey includes larval insects, snails, and shellfish. It is eaten by humans and brown bears.
Coregonus sardinella, known as the least cisco or the sardine cisco, is a fresh- and brackishwater salmonid fish that inhabits rivers, estuaries and coastal waters of the marginal seas of the Arctic Basin, as well as some large lakes of those areas.
The schelly is a living fresh water fish of the salmon family, endemic to four lakes in the Lake District, England. Its taxonomy is disputed with some recognizing it as a distinct species and others as a variant of the widespread Eurasian whitefish species Coregonus lavaretus. It is present in Brothers Water, Haweswater, Red Tarn and Ullswater, and the population seems stable in all of these except for Haweswater where it seems to be declining. The main threats it faces are seen to be water abstraction and cormorants, and the fish-eating birds are being culled from Haweswater. The International Union for Conservation of Nature has rated the conservation status of this fish as "endangered".
The freshwater whitefish are fishes of the subfamily Coregoninae, which contains whitefishes and ciscoes, and is one of three subfamilies in the salmon family Salmonidae. Apart from the subfamily Coregoninae, the family Salmonidae includes the salmon, trout, and char species of the subfamily Salmoninae, and grayling species of the subfamily Thymallinae. Freshwater whitefish are distributed mainly in relatively cool waters throughout the northern parts of the Northern Hemisphere.
Coregonus artedi, commonly known as the cisco, is a North American species of freshwater whitefish in the family Salmonidae. The number of species and definition of species limits in North American ciscoes is a matter of debate. Accordingly, Coregonus artedi may refer either in a narrow sense to one of the several types of cisco found e.g. in the Great Lakes, or in a broad sense to the complex of all ciscoes in continental North American lakes, Coregonus artedi sensu lato.
The gravenche, also known as the Lake Geneva whitefish or the little fera, is a presumably extinct freshwater fish from Lake Geneva in Switzerland and France.
The peled, also called the northern whitefish, is a species of freshwater whitefish in the family Salmonidae. It is found in northern Europe and Asia.
Coregonus fontanae, also known as the Stechlin cisco, Fontane cisco, or Fontane's cisco, is a putative species of freshwater whitefish in the family Salmonidae endemic to the Großer Stechlinsee in northern Germany. It is believed to have recently evolved from the sympatric vendace, Coregonus albula.
Coregonus maraena, referred to in English as the maraene, maraena whitefish, vendace, cisco, lake herring, lake whitefish or the whitefish, is a whitefish of the family Salmonidae that occurs in the Baltic Sea basin - in the sea itself and the inflowing rivers, and in several lakes as landlocked populations. It is found in Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Netherlands, Norway, Poland, Slovakia, Russia and Sweden. As of 2013, it has been listed as a vulnerable species by the IUCN and as endangered by HELCOM. It is an extremely important fish within the Baltic Sea ecosystem, both for population equilibrium and for the local diets of the surrounding human population. Due to a variety of factors, mostly overfishing, the maraena's population dwindled to near-extinction levels. Thus, rampant repopulation was enacted to preserve this important fish.
The Peipsi whitefish is a freshwater whitefish of the family Salmonidae that naturally occurs in Lake Peipus on the border of Estonia and Russia, from where it also ascends to Lake Võrtsjärv to spawn. It has been introduced in Lake Burtnieks (Latvia), Gulf of Riga, many lakes of northern Russia, Poland, Germany, Netherlands, Japan, Lake Sevan (Armenia) and Balkash (Kazakhstan). It is a benthopelagic fish up to 60 cm long.
Coregonus widegreni, also called the Valaam whitefish, is a putative species of freshwater whitefish, a part of the common whitefish complex from Northern Europe. It is a demersal form of freshwater whitefish that feeds on benthic invertebrates. It spawns in late autumn, and can reach a length of 55 cm maximum. It is characterized by a low gill raker density.
Coregonus pallasii is a putative species of whitefish in the family Salmonidae, part of the Coregonus lavaretus complex.